The present invention relates to an apparatus and a process for reclaiming fuel oil from waste oil, and more particularly, to an apparatus and a process for turning environmentally hazardous waste lubricating oil into a high quality diesel engine fuel oil together with a relatively small amount of environmentally innocuous solid petroleum coke.
Waste lubricating oils are defined here as any lubricating oil such as engine oil, metal cutting oils and hydraulic oils.
Lubricating oil is usually produced from a certain boiling range(typically 300 to 500 degrees Celsius) cut of conventional crude oil. This material is usually called "Bright stock" and accounts for about 70% to 80% of typical lubricating oil. The remainder consists of various additives and they tend to be polymeric in nature.
Lubricating oils, while performing their job, ultimately deteriorate in their ability to satisfactorily perform any longer and have to be periodically changed out. While performing their job they pick up dirt and heavy metals both from the metal parts of the engine and from the fuels used in the engines and a typical used oil may contain significant quantities of chromium, cadmium, zinc, and lead. Break down of the hydrocarbons making up the lubricating oil can also result in lower boiling point material being present. Handling of the used oil after removal from the engine can result in light solvents being added to it along with significant quantities of water.
Therefore, used lubricating oils are environmentally hazardous and have to be treated accordingly.
The apparatus for reclaiming useful oil products from waste oil is described in, for example, U.S. Pat. No. 5,286,349 and U.S. Pat. No. 5,271,808. In the apparatus described in the above patents, a similar means of using a conventional kettle type boiler is used for recovering some of the material being boiled in the pot.
FIG. 1 is a partial diagrammatic view showing a part of the conventional apparatus for reclaiming a useful oil from waste oil.
Referring to the FIG. 1, the conventional apparatus 70 for reclaiming a useful oil product from a waste oil comprises an evaporator 80 and a condenser or heat exchanger 80. The evaporator 80 has an evaporation chamber 82 including an inlet for the waste oil, and an outlet for vaporized oil.
In the aforementioned patents, the lighter boiling components are distilled off and condensed. In the process, a significant amount of heavy material is carried over and requires a second independent distillation in an apparatus that is protected under U.S. Pat. No. 5,271,808. All of these patents are quite specific to the design details of the specific piece of machinery. They include fine detail on the construction of the equipment and control strategy. The vessel used for the cracking pot is rectangular in shape and does not have the ability to expand and contract without permanent deformation and does not produce a high quality product. Nor does it have the capability of controlling the boiling range of the product. As produced the fuel is not acceptable to a typical diesel engine, it requires significant refining before it can be so.